Siman - Eruvin Daf 91

• Roofs, chatzeiros and karpafs are each an individual reshus

The Mishnah on Daf 89a introduced the three opinions of Rebbe Meir, the Chochomim and Rebbe Shimon regarding carrying on roofs, and in chatzeiros and karpafs. Rav Yehudah said, that upon careful analysis you will find that according to Rebbe Meir, גגין רשות לעצמן חצרות רשות לעצמן קרפיפות רשות לעצמן – carrying between roofs, or between chatzeiros or between karpafs is permitted when they are owned by different people who did not make an eruv. It is not permitted to carry from one category of reshus to another.

Rashi explains that roofs, chatzeiros and karpafs are not constantly in use and are each considered one reshus. The reason why one may not carry between them is that they are each considered a different reshus because of חלוק תשמיש ושינוי שם הרשות – each has a different use and a different name.

• Karpafs are different than roofs and chatzeiros

Rav Yehudah said that according the Chochomim of our Mishnah, who prohibit carrying between roofs belonging to different owners, גגין וחצירות רשות אחד – roofs and chatzeiros are one reshus, meaning one may carry between roofs and chatzeiros that are owned by different people, קרפיפות רשות אחת הן  - and karpafs are one reshus, and one may carry from one karpaf to another even if they are owned by different people. But carrying between a karpaf and a chatzeir or roof is forbidden, even if owned by the same person. Rashi explains that one may carry between roofs and chatzeiros because תשמישן שוה, their uses are similar, but one may not carry from a roof or a chatzeir to a karpaf, or vice versa, שאין תשמישן שוה – their uses are not similar.

• The halachah is like Rebbe Shimon

In the Mishnah on Daf 89a, Rebbe Shimon stated that roofs, chatzeiros and karpafs are all one reshus in regard to items that began Shabbos in one of them. Rav said the halachah is like Rebbe Shimon והוא שלא עירבו – provided that the residents of each chatzeir have not joined in an eruv with the residents of their own chatzeir, אבל עירבו לא – but if they, residents of the chatzeiros have joined in an eruv with residents of their own chatzeir, but not with residents of the other chatzeiros then even Rebbe Shimon did not permit carrying from one chatzeir to another, דגזרינן דילמא אתי לאפוקי מאני דבתים לחצר – for we decree this is prohibited for fear that one may come to carry out utensils that began Shabbos in the house from one chatzeir into another chatzeir. Shmuel and Rebbe Yochanan disagree and say, בין עירבו בין שלא עירבו – the halachah is like Rebbe Shimon whether or not the residents of each chatzeir have joined in an eruv. They were not concerned that people will also carry items that were inside. The Gemara brings several Baraisos which seem to support Rav or Shmuel and Rebbe Yochanan and refutes them all.